When Brook Lopez went down with a stress fracture in his right foot, it left the Nets with a gaping hole at center.

But for Mehmet Okur, who the Nets acquired to replace him, it was an opportunity to prove he’s ready to be a healthy and productive player again.

“I’m happy and excited to be here, and to be able to play with Deron Williams again.” Okur said after practicing with his new teammates for the first time yesterday. “It’s good to be here, a good feeling.”

Okur, who was an All-Star in 2007 while playing alongside Williams in Utah, has long been one of the league’s top shooting big men. But after the 32-year-old tore his Achilles tendon late in the 2009-10 season, he has spent the better part of the last 18 months trying to regain his health.

He spent most of last year on the shelf after trying to rush back from the injury. That, in turn, led to back problems, and Okur wound up playing in just 13 games all season.

“I kind of came [back] early, because I wanted to play,” he said. “Then I hurt my back, and it was kind of back-and-forth. I’d play a couple games, then I felt great, then a couple games later I was hurt again.

“It was a rough year for me, but I feel great now and I’m ready to go.”

It initially looked like the Nets’ hopes of making the playoffs in their final season in New Jersey — not to mention their dream of landing Magic star Dwight Howard to pair with Williams when they move across the Hudson to Brooklyn next season — went up in smoke when Lopez was injured.

But if Okur can return to the form he showed before the injury, when he posted five consecutive seasons of at least 13 points and seven rebounds per game, including three with at least 17 points per game, he’s a more than capable replacement.

After getting a chance to rest and rehab his lingering injuries, Okur was able to play eight games in his native Turkey during the lockout, averaging 12 points and 8.2 rebounds in just under 30 minutes a night.

“I feel great,” he said. “I’ve been playing basketball for the last four months. I came [into training camp] in great shape, and I’m ready to go.”

But even a healthy and fit Okur was deemed to be surplus goods in Utah, where, thanks to the trade the franchises made last season for Williams, they have several quality young big men. Between starters Paul Millsap and Al Jefferson, as well as second-year pro Derrick Favors, who the Nets took third overall in the 2010 draft, and Enes Kanter, taken with the third pick in the 2011 draft, which originally belonged to the Nets, there was no room for a 32-year-old center coming off an injury-plagued season.

“I have no problem with that,” Okur said of Utah’s youth movement. “It’s time to move on, like it or not, so I’ve got to look forward to playing with New Jersey now.”

Yesterday’s practice was the end of a wild 24 hours for Okur. After he arrived from Utah early yesterday, he met with Johnson at the team’s facility before practice.

“He went through the whole practice,” Johnson said. “He’s really excited about being here.

“It’s probably gonna take a week or two for him to really get in sync with what we’re doing, but we don’t have more time now. We’ve got to play games.”

* Johnson said everyone on the roster will be available for tomorrow’s season opener in Washington, with the exception of rookie forward Jordan Williams, who continues to recover from a bout with dehydration.